Until now, the data has been piecemeal and it's been difficult to pin down a definitive answer. But a new report from the FBI claims that active shooter incidents have increased from 2000 to 2013.

The FBI found that 486 people were killed in 160 active shooter incidents that occurred between 2000 and 2013, with an upward trend during that time period. The vast majority of these shootings — 70% — occurred in businesses or schools, and 60% of them ended before police got to the scene.

Here's a look at the numbers:

FBI

While the number of incidents per year seems a bit random, the FBI maps out an upward trend.

There also appears to be an upward trend with the number of casualties (not including the shooters themselves):

FBI

Here's a more detailed look, separated deaths from injuries:

FBI

And most active shooting incidents occur not in schools, but in places of business (although the report does note that school shootings account for some of the highest-casualty incidents):

FBI

Overall, this report looks pretty comprehensive. While the definition of "mass shooting" varies depending on who you ask, making it difficult to figure out whether or not these threats are actually increasing, the FBI adopted a broad definition in its report. The agency looked at active shooter incidents as defined by individuals who are "actively engaged in killing or attempting to kill people" in a populated area with the use of a firearm.

The FBI notes that only 40% of the incidents included in the report would have fallen under the federal definition of "mass killing" in which three or more people were killed.

That's because unlike other studies that only looked at school shootings or mass killings with several fatalities, the FBI's report looks at active shooter incidents without factoring in the death count and it leaves out shootings that were related to gang and drug violence, accidental discharges, and public suicides.

The FBI does note that the study may have missed some active shooter incidents, but the agency is confident that the report includes the vast majority of these incidents.